Automatically identify text encoding and convert to target encoding!

When PHP processes pages, we use functions such as iconv or mb_convert to convert character sets, but this actually has a premise. That is, we must know in advance what encoding in and out are so that we can perform the correct conversion.

Although most conversions are between gbk and utf-8, what if you don’t know the encoding of the conversion object? Google has come up with such a function safeEncoding, which can easily identify the encoding of UTF8 and GBK. This function is very accurate to a certain extent, but it is not so easy to use in some more complex environments. Below I combine the differences between GBK and UTF-8 encoding and use regular expressions to determine UTF-8 Encode and use the mb_convert_encoding function to convert. In China, the most popular encodings are GBK and UTF-8, so this function automatically converts these two encodings.

/**
* Source URL: http://www.xuehuwang.com/read-450.html
* Author: Xuehu Blog
* @ string Text to be converted
* @ encoding Target encoding
**/
function detect_encoding($string,$encoding = 'gbk'){
 $is_utf8 = preg_match('%^(?:[x09x0Ax0Dx20-x7E]| [xC2-xDF] [x80-xBF]| xE0[xA0-xBF][x80-xBF] | [xE1-xECxEExEF][x80-xBF]{2} | [x80-xBF]{2} | [xF1-xF3][x80-xBF]{3} | xF4[x80-x8F][x80-xBF]{2} )*$%xs', $string);
 if ($is_utf8 && $encoding == 'utf8'){
 return $string;
 }elseif($is_utf8){
 return mb_convert_encoding($string, $encoding, "UTF-8");
 }else{
 return mb_convert_encoding ($string, $encoding, 'gbk,gb2312,big5');
 }
}